A. Field
The present invention concerns a device for drying a compressed gas.
B. Related Art and Summary
In particular, the invention concerns a device for drying compressed gas in a non-dissipative manner, in other words a device whereby the heat of the compression, present in the compressed gas, is used as a whole or partly to regenerate the desiccant, and whereby the entire supplied gas flow flows integrally through the device, without any part of this gas being blown off in the atmosphere or being fed back to the input of the device, which results in that such a device has a better efficiency than certain existing devices.
In particular, the invention concerns a device for drying a compressed gas in a non-dissipative manner, which mainly consists of a supply of compressed gas, for example in the shape of a compressed air compressor, at least two pressure vessels with an input and an output and a take-off point for compressed gas consumers.
Such devices are already known, whereby the above-mentioned pressure vessels are filled with a desiccant and whereby the gas to be dried is sent through a first regenerating pressure vessel so as to absorb moisture from the desiccant, by making use of the heat of said compressed gas, and to thus regenerate this desiccant, and whereby this gas is subsequently cooled by means of a cooler to be then guided through a second drying pressure vessel where this cooled gas is dried by the desiccant.
As soon as the desiccant in the drying pressure vessel is saturated, the flow-through sequence of the pressure vessels is reversed, such that the first pressure vessel becomes a drying vessel, whereas the second pressure vessel is turned into a regenerating pressure vessel.
Thus, thanks to the alternating use of the above-mentioned pressure vessels as a drying and regenerating pressure vessel, one pressure vessel will always be regenerated by the compressed gas, whereas the other pressure vessel makes sure that this compressed gas is subsequently dried.
The known devices for drying a compressed gas in a non-dissipative manner are disadvantageous in that they are provided with a large number of pipes and valves for reversing the pressure vessels as regenerating and drying pressure vessels, and in that they are very large and expensive and have a complex, non-modular design, such that a large number of variants need to be supported, which increases the development, production and maintenance costs.
In order to make the existing devices less complex, use is sometimes made of three-way and/or four-way valves, which are much more expensive and less reliable than conventional two-way valves, such that the operational reliability of the installation as a whole is strongly reduced.
An additional disadvantage for devices with a larger capacity for drying compressed gas is that it is often impossible, or at least economically inefficient to find 3-way or 4-way valves which meet the demands as far as required temperature, pressure and flow are concerned.
The present invention aims to offer a device for drying a compressed gas in a non-dissipative manner which does not have the above-mentioned and other disadvantages and which can be applied to different types of adsorption drying devices in a simple and cheap manner.
To this end, the present invention concerns a device of the above-mentioned type for drying a compressed gas in a non-dissipative manner, whereby this device is additionally provided with a first distribution device onto which the above-mentioned compressed gas supply and the take-off point are connected and which is moreover connected to each of the above-mentioned pressure vessels, and with a second distribution device which is provided with one or several coolers and which is connected to each of the respective inputs of the above-mentioned pressure vessels, whereby the above-mentioned first and second distribution device are connected to each other, and whereby the device can be controlled by means of nine or ten cut-off valves.
By cut-off valves are meant valves which can be controlled manually or in an automated manner, in other words which can be opened and closed. Non-return valves which cannot be controlled as such are consequently not regarded as cut-off valves as meant here.
A really major advantage of such a device according to the present invention is that it only has to be provided with a relatively limited number of valves compared to the existing devices for drying a compressed gas in a non-dissipative manner, as a result of which the device is cheaper and requires less maintenance costs.
If the above-mentioned valves are made in the form of automatically controlled valves, use can be made in this specific construction of a relatively simple control system with a limited number of inputs and outputs, and the control program is simplified as well in comparison with the known devices.
In a preferred embodiment of a device according to the invention, the above-mentioned first and second distribution devices are each built symmetrically and/or modularly.
By a symmetrical construction of the distribution devices is meant a functional symmetry in this case, and not so much a strictly geometric symmetry. This implies that the distribution devices can be made asymmetrical in shape, but that the device can be represented by means of a symmetrical functional diagram.
A major advantage of such a device according to the invention is that, thanks to the symmetrical construction, it contains a large number of common parts, such as for example pipes and pressure vessels, which can consequently be produced in larger numbers and thus in a cheaper manner.
Another advantage of a device according to the invention is that, thanks to the symmetrical construction, the above-mentioned distribution devices can be mounted one above the other, such that the length of the connecting lines between both distribution devices is reduced to a minimum, the device is reduced in size, and costs are saved.
Another advantage of a device according to the invention is that, thanks to the combination of the modular construction and the symmetrical arrangement of the distribution devices, one and the same distribution device can be combined with pressure vessels having different diameters. Since the diameter of the pressure vessels, as opposed to the diameter of the pipes in the distribution device, strongly depends on the flow rate to be dried, there are usually many more variants of the pressure vessels than there are variants of distribution devices.
Since, according to the invention, variants of distribution devices and pressure vessels are independently interchangeable, less different parts will need to be kept in stock and production costs can be saved.